


flyin' above the sunset

by luxnoctre



Category: Haikyuu!!
Genre: Alternate Universe - Avatar & Benders Setting, Bokuto the Sidekick, Fluff, M/M, Mentioned Other Atsumu Pairings, Mild Swearing, Osamu being an idiot for once, Tiny bit of implied drug usage, Water Tribe Necklace, no beta we die like men, outsider's POV
Language: English
Status: Completed
Published: 2020-06-27
Updated: 2020-06-27
Packaged: 2021-03-03 19:21:24
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 6,222
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24940735
Author URL: https://archiveofourown.org/users/luxnoctre/pseuds/luxnoctre
Summary: All hell breaks loose in the Northern Air Temple when Osamu discovers a Water Tribe betrothal necklace in his brother's room. Except, there's just one small problem:Who gave it?
Relationships: Miya Atsumu/Sakusa Kiyoomi, Miya Osamu/Suna Rintarou, mentioned
Comments: 36
Kudos: 695
Collections: sakuatsu/, ~SakuAtsu~





	flyin' above the sunset

**Author's Note:**

> Honestly, considering how large of a part ATLA played in my childhood, I'm surprised I didn't write an AU like this sooner. Anyways, this actually took me longer than I expected (curse you writer's block and burn out) but I hope the result is still good~ It's been a while since I finished something 
> 
> Enjoy! And thank you for all the support~
> 
> side note: yeah i know canon atla dictates that airbenders are bald but im not gonna do that so lets pretend that the monks let our boys slide because imagine the twins not having hair? you wouldn't be able to tell them apart first off, so yeah, they have hair

It was a perfectly normal day, well, as normal as it could be in the Northern Air Temple, for Osamu. Waking up to the sound of his air bison bellowing right beside his ear, fixing his hair with a well practiced rush of air. He was thinking he would try guava juice for breakfast today (supposedly it would do wonders for his complex) and maybe go out to the courtyard to practice air ball. But first, Osamu had to wake up his twin brother.

It was a perfectly normal day, until Osamu slammed open Atsumu’s door, mouth ready to yell obscenities, and he saw the flash of blue on his brother’s desk.

Blue? Air benders didn’t exactly own anything  _ blue.  _ Not that they had bad fashion taste or anything of the sort. Air benders were known for their conservative clothing for a reason. It allowed them to form a deeper connection with nature, or so the monks said.

Osamu thought it was just in case that, if an air bender fell into one of the many mud puddles littering the outskirts of the temple, it wouldn’t stain their clothing. It also was useful for blending in to pull tricks and jokes on other benders. Not that he ever did that of course.

But this blue was too striking to be anything of Atsumu’s. His twin wasn’t in his room, so Osamu quietly closed the door behind him and crept up to the desk. It was half slotted in an envelope, and was attached to a dark blue ribbon with gold fastings. 

He pulled it out of the confines of the paper, and promptly choked in surprise. 

It was a Water Tribe necklace. 

A necklace? Osamu thought hurriedly to himself. There’s only one reason why  _ any  _ water bender would give a traditional necklace to another person. But that would be ridiculous. Maybe it was just-

Osamu flipped over the blue pendant, carved carefully out of shell and glass, and wheezed at the inscription. 

_ To Atsumu, my love _

He put down the necklace. Carefully, not to damage the pendant. Osamu’s face was perfectly expressionless, until he walked over to Atsumu’s bed, took one of the pillows, and screamed enough curses that would get him laundry duty for a week from the monks.

Atsumu was  _ engaged _ . Or, at the very least, being courted.

Him. Osamu’s twin brother. An utter moron in Osamu’s eyes. Had some moony eyed water bender chasing after his love and affection. 

Meanwhile, Osamu could barely get his own fire bender boyfriend to give him the time of the day.

Was this karma? Osamu wanted to ask his ancestors. Was this karma for the time that Osamu stole Atsumu’s air bender stick (stick, not staff, he was particular about this) and used it as a duster? Or when he poured lava rocks into Atsumu’s shoes and watched his twin walk around with blisters for a week. Because if it was, well, then Osamu had to have a serious conversation with the monks about clearing his chi. 

But there was a problem. Just a small problem, Osamu realized to himself.

Who the  _ hell  _ in the Avatar’s good name gave Atsumu the necklace? 

The twins had plenty of water bender friends, in fact, a few of them were at the temple at that very moment. But Osamu wasn’t exactly sure who out of all of them would give Atsumu a courting necklace. In classic Water Tribe tradition, giving a hand made necklace to one’s love was essentially declaring their intentions to cherish and care for them forever. It was most commonly used for marriage proposals. 

In short, it was something serious, and nothing Osamu could take lightly.

Examining the necklace further, Osamu could tell that the bender put in hours of effort on the pendent. The design was relatively simple, a fusion of the air and water bender symbols, similar to the Yin and Yang symbols, but the precision in the marks was plain to see. The material caught the morning light and sparkled like icicles when Osamu raised it up. The necklace was light, but the pendant certainly was large enough to catch anyone’s eye. 

Gorgeous. Clearly made by someone who loved Atsumu. 

There was no way he could tell Atsumu that he found the necklace-his twin would rather throw himself into a pit of bison feces than reveal the name of the water bender. Osamu would have to take this interrogation in his own hands.

He stepped out of Atsumu’s room, checking for anyone in the hallway, before slinking away to the courtyard. Unfortunately, Suna was away from the temple and out on a training mission with his fellow fire benders. So Osamu was alone in his efforts. 

Osamu would have to approach this carefully.

Currently, Osamu was aware of four water benders that would have any potential to court Atsumu. And luckily for him (unluckily for them) all of these mentioned benders were in the Northern Air temple for a cultural exchange. Plenty of time for Osamu to interrogate both them-and his brother.

The appearance of the necklace conjured up a whole slew of childhood memories. Bits of conversation Osamu had with his brother when they were younger flowed to the front of his mind.

_ “‘Samu, who do you want to marry when you grow up?” _

_ Osamu glanced over at his brother, who was sitting on one of the courtyard railings, feet dangling merrily over the abyss below. “Why are you asking that, ‘Tsumu?” _

_ “I dunno.” Osamu sat beside Atsumu as his brother leaned against his shoulder. “I heard some of the monks talking about it, so I was just thinking.” _

_ “Hm, well, someone strong then,” Osamu decided, “And cute! And will eat lots of snacks with me!” He patted Atsumu’s head softly with his hand. “What about you?” _

_ “I’m not sure.” _

_ Osamu hummed lightly, peering over the edge. He could see some airbenders flying down there. Maybe he should join them, but he’d rather stay up at the temple, talking with his brother, watching the clouds drift hazily past. “Well, nothing wrong with that,” Osamu said, “The monks told us that relationships are really important.”  _

_ When Atsumu didn’t respond, Osamu tilted his head, peering curiously at his twin. If he wasn’t mistaken, there was a look of nervousness on Atsumu’s face. “What’s wrong?” _

_ “What if no one likes me back?” _

_ Young Osamu didn’t understand much at that age. He understood how to airbend a strong wind, how to bake pork buns, and how to fold his clothing neatly. Maybe on a good day, he would remember his lessons too. But when it came to his brother, Osamu felt a certain level of link that was only possible because of their closeness. _

_ “Someone will,” Osamu assured. A thought popped into his mind and he added, “And when you find that person, I’ll make sure they treat you correctly.” _

_ “Really?” Atsumu asked hopefully. _

_ “Of course.” He playfully pushed at Atsumu’s shoulder. “The only one allowed to annoy you is me!” _

_ Atsumu laughed and jumped off the railing balcony. “Race you to the kitchens!” Osamu wasn’t one to back down from a challenge, so he leaped off, sprinting after his brother, childhood promises and hopes echoing in his head _

It’s been at least ten years since that incident, but Osamu still remembered it clearly. It seemed insignificant back then, just another piece in their brotherly bond. But when faced with the actual reality of Atsumu being courted, Atsumu in love, Atsumu  _ leaving _ .

That childhood promise suddenly felt a whole lot more serious. 

If Atsumu really was getting married, then the least Osamu could do was ensure that his brother was happy. 

Speak of the devil-

“‘Samu! Your hair looks like crap, wake up on the wrong side of the bed today?”

“And if I did, what’s your excuse?” Osamu promptly yelled back. Atsumu grinned at him, cheeky and satisfied, from where he was talking to the other air benders. 

“‘Hey, hey, Samu!” Osamu felt someone grab his shoulder in a fit of energy. “You’re late for our sparring practice.” The air bender smiled in apology, mind already plotting his next move. The water benders were only at the temple for a short while. He’d have to be fast.

“Sorry, Bokuto, I was cleaning up the kitchens,” Osamu excused himself, “We can practice right now.” The first victim to his questioning: Bokuto Koutarou, a water bender whose flamboyant style made for flashy moves, great for entertainment, challenging for combat. 

Bokuto was close enough to Atsumu to give him a necklace, Osamu thought, as he and Bokuto walked to one of the training areas set aside for them. But his interactions with Atsumu were a little too much on the platonic rather than the romantic side.

Well, it wouldn’t hurt to ask a few questions.

“So, Bokuto,” Osamu started as they set themselves in their starting positions. He had his arms out, palms raised, and was resting his weight on the tips of his toes for maximum speed. “What do you think about Atsumu?”

“Hm? Atsumu?” Osamu took Bokuto’s momentarily look of confusion to launch a cutting gust of air, but the water bender dodged it and sent a whip of water immediately back. The water curled like a snake, aiming to wrap around Osamu’s ankles. He jumped over the attack, floating for a few seconds in the air. “Tsum-tsum is great! He’s so fun to duel!”

“Is that it?”

“Well, sometimes his jokes aren’t as funny as he thinks.”

Osamu would have to agree with that. Atsumu wasn’t nearly as funny as he thought he was. 

“But he’s a great friend!” 

“ _ Just _ a friend?”

Osamu realized after he said that that his tone might have been a little too suspicious, because Bokuto pulled back with a curious look on his face. Then the water bender laughed loudly, lowering his guard as he clapped his hands in amusement.

“Oh do you think I’m interested in your brother?” Bokuto asked. Osamu hesitated for a moment, but nodded. “That’s funny! Don’t worry! Atsumu is an amazing friend but he’s just a friend. Besides, there’s someone else I’m interested in.”

Ah, right. Osamu mentally face palmed himself when his memory conjured up images of Bokuto chasing after a serious earth bender. That was one water bender down, and personally, Osamu was a bit relieved. Handling Bokuto as a friend was already enough, handling him as a brother-in-law would be akin to an emotional torture. 

In a good way. Mostly.

“Why are you asking?” 

Osamu took a moment to assess the risks of telling Bokuto what happened. On one hand, it would be a great help getting the water benders alone. On the other hand, Bokuto was like a bomb that Osamu had no way of defusing and he might accidentally expose something to Atsumu. Well, any help would be useful at the moment. 

“I’m just looking to pair my dear brother off with someone.” Anyone who knew Osamu for a long period of time would easily detect the drip of sarcasm in his voice, but Bokuto looked genuinely delighted by the idea.

He nodded his head in understanding and asked, “Oh! So are you asking all us water benders? Trying to figure out which of us are the most compatible?”

“Something like that.” 

“Well, why didn’t you just say so?” Bokuto beckoned Osamu to come closer, a mischievous smile on his face. “I want to see Atsumu happy too, so I’ll help you.”

“Know if any of the water benders are interested in him?” Osamu whispered back, an identical grin on his face. 

Bokuto hummed thoughtfully, eyes scanned the rest of the training arena. “I saw Sugawara talking to him at dinner yesterday, if that helps.”

Sugawara huh? “Thanks, do you think you could get me alone with him?”

“Sure! After training, he usually heads to his room to prepare for meal time.”

“Wonderful.” Osamu stuck out his head in a mock gesture of seriousness, and smirked. “Thank you for your help, dear Bokuto.”

“Anything for you, dear Osamu,” Bokuto replied, immediately following his lead. “Hey! In exchange, you have to teach me how to fly, ok?”

“Water benders can’t fly, Bokuto.”

“Well, normal water benders can’t!” 

Osamu gave Bokuto a long look, but the water bender still had his brilliant bright smile on his face, as if he didn’t just suggest the impossible. What it must be like, Osamu wondered, to have the spirits on your side. 

“I’ll see what I can do.”

\----

Osamu couldn’t exactly say that he was the best of friends with Sugawara. Sure, they talked and trained together. But Osamu didn’t know much about the silver haired bender beyond the things he'd heard. Hinata said that Sugawara was a bright ray of sunshine, a high compliment from someone nicknamed “sun child.” According to the words of Kenma, a mildly absent minded looking air bender, Sugawara was the devil incarnate. 

How perfect for Atsumu.

After training ended, Osamu did his best to try and tail Sugawara up to where the water benders were staying. But his path was blocked by a line of air bison pups (how precious) and a bushy eyed Atsumu, who was looking for another duel. He had to accept (one didn’t just back down from a challenge) and the entire time Atsumu was throwing spinning balls at him, Osamu itched to yell at him about the necklace.

Stay quiet, Osamu told himself, it would be better to find out himself, and then mercilessly tease Atsumu about it for the next five years. It would be the greatest thing Osamu could hold over his twin’s head, all in revenge for the borderline ridiculous childhood incident that would not be mentioned but Atsumu always used.

Luckily, there were a few hours of downtime later in the day, after the monks’ studying and meditation. Osamu loved and hated meditation. He loved it because it was the time he could relax out his muscles and let his chi flow through him, coursing through his body like a river of energy. 

And if he had Monk Gyatso monitoring the session, then Osamu might get lucky and be able to have a different type of energy rush through his body. 

But on the completely opposite side of the coin, meditation was an utter shitshow when one had a group of rowdy air and water benders locked in a garden for two hours. It was the perfect time to pull pranks and gossip among themselves, and naturally, Osamu was not immune to these temptations.

“Osamu,” Atsumu hissed angrily from the rock he was sitting on. Osamu snickered under his breath when he heard his brother muttering to himself. “Stop blowing my clothes around, it’s distracting.”

“I’m hardly doing anything, brother,” Osamu replied tranquilly, eyes closed and fists clasped together. “I feel hurt that you’re accusing me of such groundless claims.” 

“Um, guys, we still need to concentrate on breathing,” Asahi reminded them nervously. His long hair blew serenely around his face as he peeked at the twins.

“It has been three days, and Bokuto is still unable to keep still for longer than ten minutes,” Another water bender murmured. Oikawa Tooru. A pretty water bender with chocolate brown hair and eyes to match. He was sitting besides the garden’s waterfall, water spraying gently around him. Osamu considered him to be a potential suspect in the bid for Atsumu’s hand. He’s heard too many stories about Oikawa’s love-capades to hold him innocent. 

“I’m doing my best, ok?” Bokuto protested. He wiggled in his spot, pouting in frustration.

“Think still thoughts, Bokuto,” Osamu’s fellow air bender, Futakachi, sighed in exasperation beside him. “I don’t understand how your chi can possibly flow through your body with you moving around like a sick lemur.”

“Maybe you shouldn’t have eaten all that plum jelly at lunch.” 

Osamu slowly opened an eye when he heard Sugawara speak. The water bender was sitting across from him, in his perfect view (and Atsumu’s, his mind duly noted). He had a smile on his face and his eyes were in small crescent moons. 

“Aw, but the plum jelly here is so delicious,” Bokuto whined. The few moments of peace and serenity in the garden was officially broken when Hinata, sitting beside Atsumu, energetically proclaimed,

“We should have a jelly eating contest!”

“That’s not a good idea, Hinata,” Kenma reminded him quietly. 

“My dear children…” All the benders immediately quieted down at the appearance of Monk Gyatso, who smiled at them fondly, a smoking pipe in his hands. Osamu could smell his natural relaxer from the other side of the garden. “As much as I appreciate you all bonding in this time, I’m not sure the spirits can feel the same way.” 

There was a low chorus of apologies before they settled back down in their respective spots. An atmosphere of quiet tranquility fell over them. Osamu inhaled a deep breath, feeling his muscles relax and unwind, before slowly opening his eyes to glance around the garden. Everyone seemed engaged in their mediation, except for Bokuto, who grinned shrewdly and nudged his head in the direction of the other water benders. Sakusa Kiyoomi, a quiet but blunt water bender, seemed to be dozing off under the shaded tree he was leaning against. Sugawara had a placid smile on his face and Oikawa looked like the model form for meditation. 

All three of them were suspects, Osamu decided. Shame he couldn’t turn around to see if Atsumu was looking at any of them. 

Out of the three benders, Oikawa was the most suspicious. Osamu had dealt with him in the past and he remembered Atsumu’s attitude towards him. The two shared a far too many similar personality traits than should be allowed. Not to mention, Oikawa would be the exact type of person to pull some sort of move like this. Nothing like proclaiming his undenying love to Atsumu by directly giving him a betrothal necklace. The sheer cheek. 

Osamu only had the mental capacity to handle  _ one  _ flirtatious bender with too few bits of common sense and too much sense for trouble. 

Sugawara, however, Osamu noted, seemed certainly nice enough. He would go through with the Water Tribe traditions and present Atsumu with the necklace as a sign of his intentions. But Osamu wasn’t entirely sure what spurred the bender to give  _ his  _ brother anything. After all, Atsumu wasn’t exactly the greatest husband material.

He meant this in a loving, familial way. 

No, Osamu mentally refuted himself, he didn’t. He could take one look at Atsumu’s shit eating smirk, his flamboyant air bender tricks, and internally cringe. Who in their right mind would marry him?

The only other water bender was Sakusa. And Osamu was at least half sure that if it wasn’t for the monks’ philosophy about respecting life and valuing all people, Atsumu would have been thrown into the nearest ocean, frozen solid in a Miya-sicle. 

Osamu could understand Sakusa’s hostility, sometimes even he wanted to beg the monks for his twin’s transfer. He thought the notoriously rowdy Southern Air Temple would be perfect for Atsumu. Not so good for his stomach (Osamu heard that the monks there used bug riddled rice plants for soup) but good for deflating his ego. 

Although apparently, there had to be certain circumstances for an air bender to migrate temples, the monks kindly informed him. At least Osamu could say he tried, for the sake of his sanity.

Maybe in a cruel twist of fate, Sakusa and Atsumu would be married to each other. A clear misplacement of romantic feelings into hostility and annoyance. But judging from the way that Sakusa’s curls flipped around his face unnaturally, clearly due to a gust of wind summoned by only one person, perhaps fate was feeling gracious. 

Honestly, Osamu would not be entirely opposed to the idea of Sakusa courting Atsumu. The water bender had fine taste in food, and knew how to keep his room and appearance tidy. He could keep Atsumu’s air head and even airier personality in check. They could make a good couple. However, the idea was so unlikely in his mind that Osamu banished the thought in favor of focusing on Sugawara.

When meditation ended an hour later, Osamu was the first one standing up. He caught Bokuto’s eye, who nodded and grabbed Sugawara’s arm. 

“Hey, Suga-chan, come over here, I want to show you something.” Bokuto pulled a confused Sugawara over to the waterfall and pointed at a random patch of grass. “What type of flower do you think this is?” 

“Bokuto. That’s grass.”

“No, no. It’s a flower. Just think about it. It has green and look, a little flower.” 

“Those are weeds…”

Osamu checked behind him, but Atsumu was already blissfully walking out of the garden. Bokuto and Sugawara’s conversation made him pause for a few seconds, but he had more important things to worry about than Bokuto’s depressingly low knowledge of plants. “Sugawara, I have a few questions to ask you.” Osamu’s tone was serious as he and Bokuto huddled around the water bender. 

“Oh? Sure! What do you want to know?” 

“What do you think of my brother, Atsumu?”

Straight to the point. 

“Atsumu? Well, he’s an amazing bender, and I really respect him.” Sugawara had an upbeat note in his voice as he smiled at the two. He didn’t seem fazed by the fact that Osamu was leaning towards him so much that they were nearly pressed nose-to-nose. If anything, he almost preened in the attention. “Why are you asking?”

“Are you close with him?”

“I mean-” Sugawara considered the question for a few seconds “-I hope so? It’s always refreshing and exciting to train with him.”

“Oh? You want to train with him?” Osamu raised a judgemental eyebrow. “As if, forever?”

“Well I don’t know about forever but-”

“No, this needs to be a forever thing. You know how big of a responsibility Atsumu is? Are you prepared to handle everything?”

“W-wait-” Sugawara looked positively confused at the intensity of Osamu’s words. He held up his hands in a sign of defense. “What’s the worst he can do? He can probably air bend me off the temple, but that’s all.”

“No, Sugawara.” Osamu placed a hand on Sugawara’s shoulder and looked at him solemnly. “I’m talking about marriage. Are you prepared to take care of Atsumu, all his flaws and-all his flaws? ” 

There was a beat of silence until Sugawara started laughing uncontrollably. “You think I want to marry Atsumu?” Sugawara wheezed out in between breaths, “That’s one of the funniest things I’ve heard this week!” 

Bokuto and Osamu exchanged a look before Osamu repeated, “Wait, so you don’t want to marry Atsumu?”

“I mean this in the nicest way possible, but definitely not. Atsumu and I aren’t compatible at all. Is that all you wanted?” At Osamu’s slow nod, Sugawara slapped Osamu’s shoulder playfully, still chuckling to himself.

Osamu had half a mind to correct Sugawara that Atsumu, in fact, wouldn’t be the worst husband, but he was much more relieved that Sugawara didn’t give Atsumu the necklace. 

“Ok, that’s all I needed to know.”

“Really? No more questions?”

“Nope, thanks for your time.” Osamu gestured at Bokuto to follow him, and hurried out of the garden. Once they were out of earshot, he swung an arm over Bokuto’s shoulder, pulling him down to whisper in his ear, “It has to be Oikawa then.”

“Are you sure?” Bokuto’s eyes were wide as he glanced back and forth between the empty hallway. “You really think Oikawa and Atsumu would be good together?” 

“You kidding? Have you seen them together?” Every time Osamu saw Atsumu and Oikawa smiling together, some innate survival instinct would tell him to walk as fast as he can in the opposite direction and hide anything he deemed remotely valuable. 

“Let me rephrase that: do you think them being a couple would be good for the rest of us?” 

“Definitely not, but, Bokuto, listen-” Osamu pushed Bokuto into a tiny empty room, closing the door “-Atsumu has a necklace.” 

Bokuto blinked at him, his head tilted in confusion. “Atsumu has a necklace,” Osamu repeated slowly. 

“A Water Tribe necklace?”

“Yes.”

“Atsumu, your brother, has a Water Tribe necklace.”

“Yes.”

Osamu could almost literally see the gears turning in Bokuto’s head as he processed the information. Then he grabbed Osamu’s shoulders, shaking him in excitement. “Oh my Avatar, is Atsumu getting married?”

“That’s what I can’t figure out! Is he getting married or just being courted?” Osamu held on to Bokuto’s hands in a similar fit of energy. Thank goodness Bokuto was also treating this like a serious incident. Osamu had a small suspicion that he may be blowing this out of proportion. “And not only that, I can’t figure out who gave it to him.”

“Tsum-tsum is in love!” Bokuto hollered, half in shock, half in glee. “This is amazing. I never thought he could pull it off but looks like Atsumu  _ does  _ have charm!” 

“Bokuto, do you now understand why this investigation is so important?”

“Oh, absolutely, I want to know who’s the mysterious bender too!”

“You cannot, under any circumstances, tell Atsumu that we know about the necklace.”

Bokuto nodded so vigorously that a part of Osamu worried for the man’s neck. “And you know what, Oikawa does make sense,” Bokuto said, “Back at the city, I did see him going into a jeweler’s home.”

That information certainly caught Osamu’s interest. Going to a jeweler would make sense. A water bender would need to learn the proper techniques, collect materials, and ensure that the necklace creation went smoothly. 

“Let’s go find that son of a  bitch .”

\----

Why was it that when Osamu didn’t want to see him, Oikawa would emerge from the randomest spots and when Osamu was actually looking for him, Oikawa was nowhere to be found? 

One would think that a loud mouthed, confident water bender would be quite easy to find, but no, Oikawa miraculously disappeared. Osamu walked through an entire floor of the temple, asking the various monks and benders if they saw him. 

“Ah, Sakusa!” Osamu called out. Sakusa, who appeared to be heading towards the kitchen, turned towards him. “Have you seen Oikawa anywhere?”

“Fortunately not.” 

“Damn,” Osamu sighed, running a hand through his hair. This was much harder than he anticipated. “Do you have any idea of where he would be? Probably with Atsumu?” 

“Atsumu? Why would he be with Atsumu? And what’s the sudden interest in Oikawa anyways?” 

“Oh well, you know, those two are close so I figured they would be together.” If Osamu paid attention, he would’ve seen Sakusa’s expression darkening ever so slightly. But he wasn’t paying attention to Sakusa, he was too busy thinking about what devilish prank he should pull on Atsumu and Oikawa on their wedding day. Clearly a much more pressing issue. “I mean I guess you wouldn’t know, it’s not like you would think about Atsumu anyways.”

“Actually-”

“Alright see you!” 

And Osamu ran off, leaving Sakusa, mouth half open and hand raised to stop him. If Sakusa had something important to say to him, he could tell him later, Osamu reasoned. First, he had to find Oikawa. 

Oikawa was in what had to be the most unlikely, and most Oikawa typical, place ever. 

“Can I ask why the hell you’re sitting in an air bison’s stable?” 

“I’m reconnecting myself with the animals.”

Osamu paused for a second, before shaking his head and asking, “Do you have time to talk?”

Oikawa grinned before clearing a spot beside him. He was nestled comfortably on a patch of hay, a stolen stash of rice cakes spilling out of a bag. “Sit, sit.” When Oikawa had sat, Oikawa turned to him with a curious look on his face. “Now what are you doing here in this humble stable?”

Osamu bit his tongue in an effort not to rise up to Oikawa’s tease. Time to be a good brother. 

“So, I’m sure you’re aware of how Atsumu can be a bit much to handle.” 

“Sure, must run in the family.” Osamu couldn’t help but roll his eyes at Oikawa’s comment. His and Atsumu’s personalities really were perfect for each other. 

“Well, you know-” Osamu must admit that he stumbled a little over his words. He wasn’t used to the whole ‘sticking up for your brother’ role, “-he can be a pain but I still want him to be happy and everything.” 

“Aw, is little ‘Samu feeling sentimental today?”

“Generous,” Osamu corrected Oikawa. “Just looking out for ‘Tsumu. He may be a pain in the ass but he still deserves to be treated well. You understand?”

Oikawa looked a bit confused at Osamu’s choice of words, but he must have rationalized it in his head because he nodded in agreement. “I know what you mean. You have to look out for the people you care for.” 

“You’re going to look out for him?”

“Of course, who do you take me to be?” Osamu gave Oikawa a look, as if asking him if he really wanted Osamu to answer that question. “Right, rhetorical question. I’ll look out for him.”

“Promise?”

Oikawa laughed and lightly shoved at Osamu’s shoulder. “Yes, I promise, no need to get all worked up! You just wait till I tell Atsumu about this.” 

“Please don’t,” Osamu responded, letting out a faint groan and covering his face. “Look, I just wanted to check in with you, make sure everything is going fine.” He stood up from the hay pile, dusting himself off. “Ah-” He turned back around “-and if I hear that Atsumu is being mistreated in any way, I'll air bend your ass off a cliff.” 

“Yes, yes, I get it. There’s nothing to worry about.” Oikawa flashed a bright smile, seemingly not bothered by Osamu’s threat. With one hand, he casually waved Osamu out of the stable. “I’ll make sure Atsumu is all perky and what-not.”

Osamu carelessly waved back, before heading back to the temple. Now that the mystery was solved, Osamu felt like there was a weight lifted off his shoulders. And maybe Atsumu and Oikawa weren’t the worst couple, if Osamu just forgot about their horrible pest personalities. They got along well together, and Atsumu could be responsible if he really put his mind to it. His cooking skills weren’t all that bad either, and Atsumu was a skilled air bender so-

Wait. Osamu stopped in his tracks. Was Osamu thinking positive thoughts about Atsumu for once? Ridiculous. All this investigating must be taking a larger toll on him than expected. Maybe he should ask Monk Gyestpo for more of his natural relaxer.

Atsumu came sprinting towards him from across the courtyard, yelling on the top of his lungs as a pissed monk chased after him.

Osamu watched as Atsumu glanced behind him, and nearly crashed his head against a pole. Dumbass.

Ah, never mind. Osamu was perfectly fine.

Besides, the investigation was over. Oikawa gave Atsumu the necklace for sure. And now, Osamu had plenty of time to antagonize his brother over it.

\----

It had been two days since Osamu confronted Oikawa, and he couldn’t help but think that something was off. 

After their talk, Osamu began to pay more attention to Atsumu and Oikawa’s interactions. They talked often, laughing and joking around with each other. Sometimes they would sit next to each other in the dining hall, throwing bits of rice at the other benders or teasing Hinata. 

But Osamu felt like all their interactions were oddly...platonic.

And that didn’t make any sense to him. He should be seeing more romantic things. Like hand holding or hugs and what not. Hell, Osamu couldn’t even recall if he saw Oikawa kiss Atsumu. Not that he wanted to, he just thought it would be natural for them to do those types of activities. After all, Atsumu and Oikawa were a couple, right?

Right?

“Hey, Suga,” Osamu whispered incessantly. He pulled the water bender aside into an isolated hallway. “I have a question.” 

Sugawara fixed him with a skeptical look as he asked, “Is this another relationship question? Because hey, I like you, but as a friend. Just saying.” 

Osamu couldn’t even bring himself to glare at the other bender.“It’s not about you,” Osamu corrected him, “It’s about Oikawa; are he and Atsumu dating?” 

“Oikawa? I don’t think so…”

“Why do you think that?”

“Well, I see him talking to this one earth bender pretty often. I think Oikawa is actually planning to give him a necklace and everything. So he wouldn’t be dating Atsumu.”

A necklace. Wait, so that meant-

“Thanks!” Osamu yelled before he ran off, in search of Oikawa. He found the water bender napping lazily on a window sill. With a gust of air, Osamu flipped his clothes over his head, pushing him against and jolting him awake.

“W-what?” Oikawa sputtered, smoothing his clothes down, a pout on his face as a result from his interrupted sleep, “What did I do?”

Osamu grabbed Oikawa’s collar, pulling him close. “Oikawa. Are you dating Atsumu or not?” 

“Dating Atsumu? No! Where did you get that idea?!” 

“The talk, a few days ago, you told me that you would take care of Atsumu.”

“Yeah, in a friendly way?” Oikawa looked shocked at Osamu’s reasoning. “Isn’t that what you meant?”

Osamu suppressed a groan as he let go of Oikawa’s shirt. It wasn’t him. Oikawa didn’t give Atsumu the necklace. Osamu couldn’t believe that this entire time, he was fooled into thinking he knew everything about Atsumu. Osamu couldn’t take it much longer, he would confront Atsumu directly about this. They were brothers, this type of thing shouldn’t be kept a secret. Osanu needed to hear this from Atsumu himself.

“Miya Atsumu!” Osamu thundered, practically kicking Atsumu’s room door down, “You need to tell me who the hell gave-”

Wait. 

Osamu’s mouth practically fell open as he took in the sight in front of him. Atsumu was sitting on his desk, eyes open in shock before he let go of someone’s face and pushed him lightly away. The person stumbled back before turning around slowly, as if they were a guilty criminal. 

Today was just a day of surprises.

“Sakusa?!” 

The trio stood in silence until Atsumu lifted his hands and said quietly, “Surprise?” 

“I’m-wait, I need to process this,” Osamu stuttered, shaking his hands. He clutched at his temples, thinking back to what he had seen in the past few days. All the looks, the teasing, the seemingly hostile interactions, they were actually romantic? Which meant-the tension Osamu felt wasn’t an antagonistic type but-

“I hate you so much,” Osamu finally let out, “And you, Sakusa, I can’t believe you two have been hiding this from me.”

“Atsumu wasn’t sure how you would react,” Sakusa explained, “And technically, I did try to tell you. But you ran off instead.”

When did he-oh, back in the hallway. Huh. “Ok, then I have a question.” Osamu pointed at them with an accusing finger. “Are you two getting married?”

“Wow, ‘Samu, you want to ship me off that badly huh?” Atsumu grinned, lacing his fingers between Sakusa’s. The gesture was actually a bit cute, Osamu thought. Actually, seeing the two of them together, they looked good as a couple. And Sakusa was just the type of person to be able to keep Atsumu in check. 

Osamu wondered why he didn’t see it all before. 

“It’s a courting necklace,” Sakusa corrected, “I’m not sure Atsumu is ready for the responsibilities of marriage yet.” 

“You’re right,” Osamu agreed to the sound of Atsumu’s protests. Osamu paused, before breaking out into a wide smile. “I’m happy for you ‘Tsumu, I really am.”

Atsumu shared a fond look with Sakusa before grinning. “Thanks!”

\----

“Suna,” Osamu whined, tugging on his boyfriend’s arm, “Will you please come with me?”

“No,” Suna responded, looking bored as he sat resolutely in his seat. “I know you just want to compete with Atsumu again, and I’m hungry.”

“I have to!” He exclaimed. Osamu flopped down in the seat next to him, clutching at his heart. “Ever since I found out about them, they’ve been nothing but all romantic and sappy and it’s disgusting! Suna-” He turned to the fire bender, determination written all over his face “-we can’t let them beat us. We’re the better couple!”

Suna let out a non committed hum as he exclaimed his finger nails. Osamu blew a strand of hair off his face before turning and glaring at the couple sitting a little ways behind them. 

Atsumu caught Osamu staring at him, before he flipped him off and pulled Sakusa into a kiss. Osamu huffed before returning the crude gesture.

“Don’t be jealous.”

“I’m not,” Osamu protested loudly, “I would just prefer Atsumu to not shove his relationship status in front of my face every time I see him. I get it, I’m happy for him but it’s still annoying.” 

“Yeah?”

“Yeah, it’s so irritating when I’m walking down the hall and-” Osamu’s words were muffled by Suna wrapping an arm around his waist and kissing him quickly.

“Can you stop complaining now?”

“I will if you do it again.” 

“No.” 

_ Fin _

**Author's Note:**

> All the love and kudos to SASS to motivating me to finish this in spite of my mild burn out, you guys are the best~ And a little shoutout to Ina (you know who you are) because your art and tweets make me so happy and I really needed those serotonin boosts 
> 
> Find me on [twitter!](https://twitter.com/oikuroos%20rel=) to cry over all things hq, or just cry, I'm not picky


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